Role of the adrenal cortex and medulla in the young rats' glucoregulatory response to endotoxin

Abstract

The importance of the adrenal gland in the 10 day old (10 d) rats' glucoregulatory response to endotoxin (ETX) was investigated. Plasma glucose, lactate, and liver glycogen were measured at 0, 2, 3, and 4 h after ETX to 10 d adrenalectomized (ADRNX), adrenal demedullated (MEDX), and sham-operated (SHAM) rats. At 24 h after ETX, mortality in the ADRNX group was a striking 86% compared with 34% and 36% in intact and SHAM groups, respectively. Mortality in MEDX rats (47%) did not differ from control groups. Although MEDX exacerbated hypoglycemia at 3 and 4 h after ETX (p < or = .05), ADRNX produced severe hypoglycemia by 2 h after ETX. Lactacidemia occurred earlier and was greater in ADRNX rats than in MEDX and SHAM rats. Unlike MEDX, ADRNX significantly decreased liver glycogen and ETX rapidly depleted the remaining glycogen by 2 h after injection. These results demonstrate the greater importance of the adrenal cortex relative to the adrenal medulla in the 10 d rats' defense against ETX-induced hypoglycemia, hyperlactacidemia, and lethality.